Unsolicited Bulk Email (UBE) has become a major
concern for Internet users due to the increasing amount of
UBE that typical Internet users receive. Many proposals for
technical and legislative remedies are being suggested, but
few proposals define UBE or list its negative effects. This
paper sets forth standard definitions and gives an overview
of UBE effects, without proposing or supporting particular
mechanisms for controlling their occurrence.

Definitions

UBE

Unsolicited Bulk Email, or UBE, is Internet mail ("email")
that is sent to a group of recipients who have not requested
it. A mail recipient may have at one time asked a sender for
bulk email, but then later asked that sender not to send any
more email or otherwise not have indicated a desire for such
additional mail; hence any bulk email sent after that
request was received is also UBE.

A common term for UBE is "spam", although that term
encompasses a wider range of intrusive transmissions. For
instance, the term "spam" originated in the realm of Usenet
news, not email. There, individuals cannot request or refuse
bulk email, although some newsgroups explicitly permit
or encourage its inclusion as a part of the group charter.

Note: the first version of this report used the term
Unsolicited Commercial Email (UCE). That term was originally
chosen because much of the early debate about UBE was
centered in the United States where commercial speech can be
regulated by the government but political and religious
speech cannot. However, on reflection, because UBE is
an international problem, the term "UCE" was changed in this
report to "UBE". Limitations on the control of UBE, such as
having to have different laws for political UBE versus
commercial UBE, will be a local matter.

Destination Operator

Internet Email is processed by origination, relay and
destination system (host) operators, primarily transmitting
messages with the SMTP mail standard. An Origination
Operator is an organization or individual that is
responsible for the host which places a new piece of email
into the Internet. A Relay Operator mediates email
transmission between origination and destination systems. A
Destination Operator is an organization or individual that
maintains or controls a service for recipients of email and
for allowing recipients to access their mail using a mail
user agent. Destination Operators may also provide relay
services and almost always provide origination service for
the same users who are recipients.

These specialized terms are used here instead of the single,
more common "Internet Service Provider" (ISP) because tens
of millions of people get their mail service from
organizations that are not ISPs. Almost everyone who gets
email at their desk at work use their employers as a
Destination Operator, but those companies are not ISPs.
Also, many people get their Internet mail through free
accounts in public libraries, schools, and so on, and the
organizations running those mail servers should be
differentiated from ISPs because they often are offering
email access as a public service.

In many cases, ISPs which provide basic connectivity have no
direct part in the problems associated with UBE. On the
other hand, all Internet mail operators must deal with UBE
problems every day. Hence, the terms introduced here include
organizations providing Internet mail service to employees,
as well as libraries and schools providing free service for
their "customers" and also includes ISPs that include email
within their set of products.

Recipient

A recipient is a person who receives email. (Programs can
also receive email, but they do so on behalf of a person.)
Most recipients usually receive email from two kinds of
senders: other people, and Mailing List Agents. Some email
addresses refer to a "role" within the organization (such as
"sales" or "postmaster") and might have multiple people
processing email sent to it, or might have a software
program respond automatically. In either case, UBE must
still be handled by the recipient.

Mailing List Agent

A Mailing List Agent (MLA) is a software program that acts
like a recipient, but does special processing upon receiving
email: it resends the email to a list of recipients. Hence
an MLA is a special form of email relay. Many MLAs are
controlled by people, but some are completely automatic and
involve no human intervention or decision-making.

MLAs are sometimes called "mailing lists" or "mailing list
managers", although these terms do not define well the roles
of the controlling software or of the people involved in
controlling the software. Other terms, such as "listserv",
are sometimes used generically but actually refer to
specific implementations of MLAs.

Note that an MLA is not a recipient because it is not the
final destination for the message, even though its email
address might have been used for the UBE. Mail sent to an
MLA will most likely be re-sent to many people, and those
people are the recipients of the original mail, even though
that mail has processed and re-sent by the MLA.

Problems Caused By UBE

Although the senders of UBE defend it as having little
difference from traditional bulk mail, it in fact is quite
different: UBE shifts almost all the costs of the message
onto the recipients and their Destination Operators. The
negative effects of UBE can be categorized into the effects
on recipients, on the recipients' Destination Operators, and
on the Internet backbone in general. Secondary effects also
are felt by Origination Operators.

Further, many senders of bulk UBE use tactics which are
often viewed as devious, and probably illegal, in order to
reduce the cost to the sender or even to hide the true
identity of the sender. Instead, costs are shifted from the
actual sender to the receiver and their Destination
operator. These tactics, which are becoming more common, are
described separately because they are only tangentially
related to UBE itself.

Effects On Recipients

End users are the ones who are most affected by UBE. The
costs, to recipients, generally fall into two categories:
real costs and social costs.

Real Costs To Recipients

UBE costs money to every recipient, as if it was sent
"postage due". Probably the most important negative effect
of UBE is the financial cost incurred transmitting it from
the Destination Operator's host to the recipient user's
host, such as through a modem. Many users have to pay their
Internet access providers by the minute. Even users with
fixed-cost Internet accounts often have to pay for the phone
time to connect to their Internet access providers.

Multiply these costs by the hundreds of thousands or
millions of users that many pieces of UBE go to, and you can
see that the cost to recipients is quite high, even without
taking into account the considerable costs to Destination
Operators and the Internet backbone.

There are other costs paid by all UBE recipients that are similar to
recipients of bulk postal mail. For instance, there is the time lost sorting
UBE from wanted mail, the time lost opening unwanted UBE that is disguised
as email that the user might want to read, and so on. As the quantity of UBE
increases, the cost of doing this sorting can become quite significant. UBE
is particularly an issue for companies where employees get email, since
dealing with UBE is done on company time, thus causing lost productivity.

Social And Personal Costs

Widespread UBE has had a significant human cost as well.
Many users know that posting to mailing lists or on Usenet
news will likely cause them to receive UBE, so they no
longer participate in what used to be the most vibrant
communications medium on the Internet. The constant fear of
irreversibly getting one's name on a mailing list has caused
many people to avoid using them altogether.

Similarly, the act of having to sort through cleverly-worded
UBE in order to find actual personal email has caused many
people not to use email to its fullest potential. These
types of effects are causing many new users to avoid
checking their mail as often as they would otherwise like,
again causing less use of what could be a valuable medium.
Use of "filters" by a recipient's email software can reduce
some of this pain, but cannot eliminate it. The current
state of filtering technology cannot distinguish between
legitimate, personal email and UBE.

Effects On Destination Operators

The costs of UBE go well beyond the recipient. Each
Destination Operator pays for each email message received
because a message takes up a certain amount of the
Destination Operator's connectivity and computer bandwidth.
Further, if the message is stored by the Destination
Operator for a recipient, the operator must pay for the
storage and the maintenance of that storage. Although the
cost of a single UBE email to an individual recipient might
well be quite small, the aggregate cost can be considerable.

Depending upon their specific business model, Destination
Operators handle the costs of UBE differently. If the
Destination Operator is an Internet Service Provider, the
costs of UBE are borne by the ISP's users, through higher
prices or lower service. If the Destination Operator is an
employer, the costs of UBE are often taken out of the
general networking budget, meaning that UBE causes lower
company profits. If the Destination Operator is someone
offering a free public mail service, UBE causes them to be
able to offer less service to their clients.

Many Destination Operators report that they bear an
additional and considerable expense, one of having to
educate people about the nature of UBE and why they are
receiving it. Because UBE tends to diminish people's desire
to use the Internet, they are more likely to complain about
it to their Destination Operators.

Effects On The Internet Backbone

UBE sent over the Internet backbone causes delays for all
Internet users. Further, because most UBE senders use
mailing lists that have outdated addresses on them, many
messages are rejected ("bounced"), causing the intended
Destination Operator to send a return response, which wastes
more bandwidth.

Effects Caused By Malicious UBE Senders

Many of the complaints about UBE, by Destination Operators,
stem from the common practice employed by UBE senders of
misappropriating services. The methods of misappropriation,
while technically easy to do, cause hundreds of thousands of
dollars of damage to Destination Operators per year by
shifting the burden of sending the UBE on Destination
Operators who are unrelated to the UBE sender.

The typical way that a deceptive UBE sender misappropriates
service is to offload return mail and complaint handling
onto an unsuspecting Origination or Relay Operator by
specifying one or more incorrect return addresses in the
message itself. They route the UBE through an unrelated
Origination Operator's SMTP service. Both of these actions
are quite easy to do and can make the source of the message
almost untraceable, particularly if the UBE sender is using
a short-lived Internet account that was obtained for the
purpose of sending this UBE. The account is used once, to do
the sending, and is never accessed again. Hence, the sender
need not care at all whether its use for this purpose is
ascertained.

Beyond the basic cost of deceptive use, the result of the
unwanted mailing often causes many complaints to be directed
at the Destination Operator that should instead have been
directed at the UBE sender. These complaints can cause
significant damage to the Destination Operator, such as by
filling up mailboxes on the mail hosts and reducing service
to legitimate users of the Destination Operator.

Conclusions

Core problems associated with UBE stem from the very low
cost on the sender and the real costs on the recipients and
their Destination Operators. There is no other common form
of unsolicited communication that shifts so much of the cost
of each message onto the recipients. The costs are
particularly high on novice users and the Destination
Operators who have a preponderance of novice user clients,
but the costs are in fact borne by all Internet users.

This IMC Report is IMCR-005 and is named UBE-DEF.

New versions of IMC reports are given new report
numbers but the name of the report remains the same.